3" augers are good for 20 to 40 foot masts
6" august have capacity of 2500 to 6800 lbs depending on the length and
YOUR SOIL TYPE. See soil info at the bottom of this message.
Longer Rod length is important to increase holding capacity..
6" augers begin to be useful for guying actual climbable small tower.
To increase the the capacity of a tower guying system, you could use
individual screw-in guy anchors for each individual guywire.
You are putting MORE RISK INTO YOUR DESIGN.by using screw-in anchors = IF
you dont understand WHY this is more risky, then you should NOT be putting
up a tower.
WHY? because you can not know for sure what each installed screw-in anchors
capacity is without testing each one.
In a concrete anchor and using a specified anchor rod design, the total
strength is a calculation of the rod material and concrete weight. These
are know values and are not dependent on soil type.
I had a 60ft 45G tower guyed at two levels with six 60" x 6"Auger screw-in
anchors.
Each screw-in anchor held one guywire.
It had a rotor, 12ft aluminum mast, thrustbearing, Tailtwiister , 40-2CD.
It stayed up 8 or 9 years and then a tree fell on it.
The anchor should have the same holding capacity and the specifications for
the guywire as the tower manufacturer specifies.
Many of the guyed tower designs require 1/4" EHS guywire which breaks at
6000 to 6700 lbs. A properly installed 66" x 6" screw-in anchor MAY HAVE
capacity in good soil - thats one guywire for most Rohn 25G / 45G / 55G.
But you have to understand that when you use screw-in anchors you are
putting MORE RISK INTO YOUR DESIGN. = IF you dont understand WHY this is
more risky, then you should NOT be putting up a tower. .
Here is soil info from a screw-in anchor manufacturer:
*Holding Power & Soil Types*
*Class 5 Soil*
Rated @ 6,500 lbs
Definition: Medium dense coarse sand and sandy gravels; stiff to very stiff
silts and clays Saprolites; residual soils
*Class 6 Soil*
Rated @ 5,000 lbs
Definition: Loose to medium dense fine to coarse sand; firm to stiff clays
and silts; dense hydraulic fill; compacted fill; residual soils
*Class 7 Soil*
Rated @ 2,500 lbs
Definition: Loose fine sand; Alluvium; loess; soil-firm clays; varied
clays; flood plain soils; lake clays; adobe; gumbo; fill
Anchor requirements are site specific. Soil type should be determined to
ensure that the correct anchors are used. Always seek professional
guidance. Anchors must be installed at an angle of 45º in the direction of
the load. Failure to install within 5º of alignment of the guy load will
significantly lower strength. Capacity ratings apply to properly installed
anchors only.
** Holding strengths are approximate and based on industry standards.
Determining soil load capacity is an inexact science limited by an inexact
environment, from all of the unknowns both below and above the surface of
any anchoring application--the soil medium, installation method, local
climate, connections to the anchored structure--no one can guarantee an
exact holding strength. Load capacity is not a simple function of “soil
class” but also of real-time moisture content, compaction, root
penetration, installation method, pullout load angle and other factors
unique to the installation’s time and place. Therefore the only way to
truly determine holding strength is on-site specific probing and testing.*
,
Longer Rod length is important to increase holding capacity..
6" augers begin to be useful for guying actual climbable small tower.
To increase the the capacity of a tower guying system, you could use
individual screw-in guy anchors for each individual guywire.
I had a 60ft 45G tower guyed at two levels with six 60" x 6"Auger screw-in
anchors.
Each screw-in anchor held one guywire.
It had a rotor, 12ft aluminum mast, thrustbearing, Tailtwiister , 40-2CD.
It stayed up 8 or 9 years and then a tree fell on it.
The anchor should have the same holding capacity and the specifications for
the guywire the tower manufacturer specifies.
Many require 1/4" EHS guywire which breaks at 6000 to 6700 lbs. A 66" x 6"
screw-in has that capacity in good soil - thats one guywire for most Rohn
25G / 45G / 55G.
But you have to understand that you are putting MORE RISK INTO YOUR DESIGN.
= IF you dont understand WHY this is more risky, then you should NOT be
putting up a tower. .
On Tue, Apr 14, 2020 at 8:16 AM Charles Morrison <junkcmp@gmail.com> wrote:
> Most screw-in anchors depend on the combination of the soil and the
> perpendicular surfaces of the screw-in anchor for its holding ability.
>
> This anchor states its maximum
>
> https://www.westechrigging.com/earth-anchor-helix-034x6x66.html?gclid=CjwKCAjwvtX0BRAFEiwAGWJyZDonvClIGL6-Fs0LW7mH4rg4NiXsl2wVVztVNDhCWe7VT0fMBPjsyxoCYPoQAvD_BwE
>
>
> Here is additional info about screw-in anchors with similar capacity info,
> again dependent on soil..
> http://w4zt.com/guy/index.html
>
> And finally, heres a big station owner's experiences and best practices:
> https://www.w8ji.com/screw_in_guy_anchors.htm
> This common anchor lists
>
> On Tue, Apr 14, 2020 at 12:46 AM K9MA <k9ma@sdellington.us> wrote:
>
>> I can't imagine climbing a tower held up by aluminum screw anchors. And
>> what if one hits a rock on the way down?
>>
>> A friend of mine learned the hard way in a storm last summer about
>> inadequate guying. Although the earth anchors held, one of the
>> undersized guy wires and wire rope clips didn't. It was about 60 feet of
>> Rohn 25 with just one set of flimsy guys. He had a hazer, so at least he
>> never had to climb it. I had seen it before it came down, but what could
>> I say?
>>
>>
>> 73,
>>
>> Scott K9MA
>>
>> On 4/13/2020 22:49, Kelly Taylor wrote:
>> > What’s that saying called again?
>> >
>> > Do what the manufacturer says to do and don’t do something that isn’t
>> what the manufacturer says to do.
>> >
>> > Some kind of prime directive? ;-)
>> >
>> > 73, kelly, ve4xt
>> >
>> > Sent from my iPhone
>> >
>> >> On Apr 13, 2020, at 21:14, Wayne Kline <w3ea@hotmail.com> wrote:
>> >>
>> >> Fred,
>> >>
>> >> Not sure of your applications for these BUT IMHO I don’t think
>> it’s an appropriate anchor for tower installation .
>> >>
>> >> All guys tower manufacture have speck for there hight/windload/anchor
>> specifications.
>> >>
>> >> Build it to spec and you can’t go wrong
>> >>
>> >> Wayne W3EA ,
>> >> Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for
>> Windows 10
>> >>
>> >> From: Fredrick Matos via TowerTalk<mailto:towertalk@contesting.com>
>> >> Sent: Monday, April 13, 2020 3:44 PM
>> >> To: towertalk@contesting.com<mailto:towertalk@contesting.com>
>> >> Subject: [TowerTalk] Guy Wire Anchors
>> >>
>> >> I have researched guy-wire anchors and found these made by the
>> American Earth Anchors Co. in Rhode Island/
>> >>
>> >>
>> >> They are pricey but the best part is that they can be easily driven
>> into the ground with an impact wrench. They have excellent pull-out
>> resistance specs. Almost too good to believe, which makes me skeptical.
>> >>
>> >>
>> >>
>> https://americanea.americommerce.com/PE46-Guy-anchor-46-inch-Penetrator-with-guying-head.htm
>> >>
>> >>
>> >>
>> >> Their home page has a video of a 4-foot model being screwed into the
>> ground in a few minutes.
>> >>
>> >>
>> >>
>> >> Has anyone used these types of anchors?
>> >>
>> >>
>> >> Or do you know people who have, and what is the result?
>> >>
>> >>
>> >> t would appreciate views and opinions.
>> >>
>> >>
>> >>
>> >> t
>>
>>
>> --
>> Scott K9MA
>>
>> k9ma@sdellington.us
>>
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|